Questions and Answers for the Higgs Particle
What is a Higgs particle?
Do you know what a particle is? Field? If not, let's understand.
A field is something
')
1. what is present everywhere in space and time,
2. able to take a zero or non-zero value,
3. that is capable of generating waves in itself.
4. And if this is a quantum field, then these waves are made up of particles.
For example: the electric field is a part of nature, and it can be found everywhere. At any given point in space at any time it can be measured. If in a certain region of space, on average, it is non-zero, it can have a physical effect — lift your hair or cause sparks. An electric field can generate waves in which the magnitude of the field periodically becomes larger and smaller - for example, such a wave is visible light, X-rays, radio waves, and everything else that we generally call "electromagnetic waves."
So what is a particle?
The intensity of the quantum field waves can not be any. They cannot be arbitrarily "weak" or "quiet." The lowest intensity wave that a field is capable of propagating is called a "quantum" or "particle." Often they behave like you intuitively imagine particles - moving in straight lines and bouncing off different things, that's why we called them particles.
In the case of an electric field, its particles are called "photons." They represent the weakest possible outbreak. Your eye can absorb light one photon at a time (although it is usually the arrival of several photons in a row to send a signal to the brain). The laser produces very intense waves, but if you shield the screen from it so that a small part of the light passes through it, you can find that the light passes through the screen in small bursts — single photons — and they are all equally dull.
I sort of got it. The Higgs wave is a perturbation of the Higgs field, and the Higgs particle is the smallest, weakest wave.
Exactly. Sorry for such a short version of the story. In the following articles there will be explanations about particles using mathematical calculations and physical bases.
Why are particle physics experts so interested in the Higgs particle?
In fact, they are not interested in her. They are interested in the Higgs field, it is extremely important for them.
Why is the Higgs field so important?
The Higgs field, unlike the most elementary fields of nature, has a non-zero average value throughout the Universe. Because of this, many particles have a mass, including an electron, quarks, and particles of weak interaction W and Z. If the average value of the Higgs field was zero, these particles would be massless or very light. That would be a disaster; atoms and atomic nuclei would disintegrate. Nothing like humans or the Earth on which we live could exist without a non-zero Higgs field average. Our lives depend on it.
What do we know about the Higgs field?
Almost nothing. Basically what it is, and that its value is non-zero. We have some information about how it interacts with matter, but not too much. The recent discovery of what may be his outrage - the Higgs particles - can give us more information.
If the Higgs field is so important, why is there so much noise around the Higgs particle?
On the one hand, finding the Higgs particle (or something instead of it — details below) is the simplest (and probably the only) way for physicists to study the Higgs field — and that’s what we need. In this sense, the detection of the Higgs particle is the first big step towards the main goal: understanding the properties of the Higgs field and the reasons for its non-zero average value.
On the other hand, modern media insist on inflating the hype. And since the explanation of the Higgs field and its role and connection with the Higgs particle takes up too much space for a typical news report, journalists, as well as people communicating with them, reduce all this information. As a result, the Higgs particle receives all the attention, and the unfortunate Higgs field works in obscurity, protecting the Universe from disaster and not receiving the deserved respect ...
Are physicists confident in the existence of the Higgs field?
Yes, although this is a point that needs special comment. On the basis of many experiments and their successful interpretations with the help of mathematical equations, we are sure that there is a certain field with a non-zero average value that gives mass to the electron, W, Z particles, and many others, and allows our world to exist with us. The evidence is indisputable. By default, we call this field the "Higgs field."
But we do not know much. For example:
• There may be one Higgs field, or there may be several — each with its own particle.
• The Higgs field can be a composite of several other fields. There are such examples in nature: if a proton is a composite object consisting of quarks, antiquarks and gluons, then the proton field is a composite field consisting of quark, antiquark and gluon fields. We do not know whether the Higgs field is elementary, like an electric field, or whether it is a composite field like that of a proton.
The only way to find out the number of Higgs fields and their elementary nature, as well as how they interact with particles known to us, and possibly with unknowns, is to conduct an experiment: the Large Hadron Collider, or LHC.
What is "elementary"?
Unfortunately, the answer is looped back: it means "not composite." It cannot be broken down into more elementary parts. More precisely, it can not be divided into parts with the help of our existing technology. (People used to think that protons are elementary. Before that, they thought that atoms were elementary - hence the “Periodic Table of Elements”).
Are physicists confident in the existence of the Higgs particle?
Previously, we were not sure of this, and its existence was essentially proved only by an experiment from July 2012.
And in the past we were sure that:
1. There is at least one type of Higgs particle, and we will find it (them) at the LHC, or
2. The Higgs particles decay too quickly for us to detect them, but only because they are greatly influenced by new particles and the forces that we can find in the LHC!
Now we have learned something: the second option was wrong. And although there might not have been a Higgs particle in nature, it seems to exist. And now, in order to learn more about the Higgs field, we need to understand whether there are other types of Higgs particles, and what are the properties of the found particle.
The press and many physicists claim that the LHC was built to search for the Higgs particle. And since they found her, did the BAC finish their work?
All this is not true. It is true that the LHC was built in order to understand what the Higgs field (or fields) is, how it works and elementary or composite. Finding a Higgs particle is one way to find out. Do not confuse goals and means. The ultimate goal is an understanding of the field. Search and study of a particle are the means, and at the LHC there is still a lot left to do, including the study of the found particle and possible discoveries of new ones.
Did you really find the Higgs particle?
Similarly, we can say the following:
1. Using the data obtained in 2011 and the beginning of 2012, the scientists discovered a new particle at the LHC.
2. This particle has not yet been very well studied, but it behaves as expected from the Higgs boson.
3. It also behaves according to how the simplest type of Higgs particles should behave - the so-called. Higgs particle from the Standard Model.
While scientists conduct additional research of this particle. These studies will also help us in expanding our understanding of the Higgs field. In addition, we will continue to search for other Higgs particles that are harder to find. The fact that we have yet found one does not mean that there cannot be two, five or twelve!
Do you really, in all honesty, solemnly swear that you are convinced that there is a Higgs field in nature?
Yes Yes Yes. I rarely say anything in absolute terms, but here I say yes. If you try to remove the Higgs field from mathematics, but leave W, Z and other heavy particles (such as the top quark) that we already discovered and are present in nature, it turns out that the mathematics of the Standard Model does not make sense. It turns out a theory that predicts that certain processes (including those that can be studied at the LHC) can occur with a probability greater than 1. And this is impossible and illogical. The probability of something, obviously, cannot be more than one or less than zero.
You may be surprised, but it is very difficult to make logically consistent theories. Most theories begin to predict events with probability less than zero or greater than one. Only a very small number makes sense.
To restore the Standard Model to its working state, you must add the Higgs field, or something like it, to the fields already open in the experiments. But this can be done in many ways, and the only way to determine which of them is correct is to conduct an experiment, namely, LHC!
Why is the Higgs particle often called the "Higgs boson"?
All particles in nature, elementary or not, can be divided into two classes, fermions and bosons (although in some solid materials there are very strange exceptions). It so happened that the Higgs particle is a boson. But in terms of what it does and why we need to look for it and study it, it is not so important.
Why is the Higgs particle called the “God particle”?
Because in the media they believe that it sounds cool and that it makes readers pay attention to their articles. The origin of this nickname is as unreligious and unscientific as you can imagine: it was invented as an advertisement. Professor, Nobel Prize winner, Leon Lederman, a very important experimental physicist who deserves great respect for his contribution to science, deserves also every censure for his book on the Higgs particle [The God Particle: Is the Question?] Got such a catchy headline. It is somewhere between indecency and blasphemy, depending on your upbringing. When I, while studying at the institute, first heard how he used this nickname during his lecture, my jaw just dropped. I already knew enough about physics to understand how absurd it was.
I have never seen or heard a physicist, thus mentioning a Higgs particle in any context — in scientific work, in a report at a conference, or even in an informal scientific discussion. Nothing in mathematical equations, in the interpretation of physics, in any of the philosophies I know, in religious texts and traditions I know of, does not unite a particle or Higgs field with concepts of religion or deity. This nickname came up from scratch.
Personally, I think that neither science nor religion should be change coins due to the fact that book publishers need to sell books, and the media - articles. The sooner we abandon this idea, the better.
I heard that the Higgs particle disintegrates very quickly, so how can it create or maintain the Higgs field? From what I read, it seems to be that there is a sea of Higgs particles, which in some way create the Higgs field. But it will not work if the Higgs particle ceases to exist very quickly.
The Higgs field does not need to be created in any process; it simply is, just as an electric field exists, everywhere and always.
The Higgs field has a non-zero mean value (and an electric value has a zero value). This nonzero value is also simply "is." It does not need to be created in any process. It is simply the preferred state of the universe for the Higgs field. We do not know why this is happening, but for this, no one should do anything.
No need to imagine the non-zero value of the Higgs field as a sea of Higgs particles; it is not right. The Higgs particle is a perturbation of a field of minimal intensity. The perturbation changes in space and time, like any wave. But the non-zero value of the Higgs field does not change in space and time, it is a constant. A good analogy: air density is a field. He has a constant average. Waves in the air are sound waves. And it makes no sense to assume that the average air density is somehow created by a sea of sound waves, fleeting air vibrations.
Higgs particles do not form spontaneously. For this you need to expend energy. You need to use something like a proton collision on the LHC to hit the Higgs field and make it vibrate, just like clapping your hands to make a sound, hit the surface of the lake to create a wave, or pull the violin string to vibrate . Just as the wave goes out after a while, and the string of the violin stops vibrating, so the Higgs particle disintegrates. The air, the lake, the strings of the violin and the Higgs field remain after the vibration dissipates.
Then it turns out that Higgs particles do not exist in nature? Apparently, therefore, you wrote that in the room where I am, there are no Higgs particles, but my electrons have mass. And what is the role of the Higgs particle in the mass mechanism? I thought that they somehow transferred the interaction, such as W for weak interaction, but it seems that the Higgs particle is not suitable for this. And in one lecture I asked Frank Close, if there were any Higgs particles in the room, and he mentioned that they could appear, “taking over” energy for a while, and then disappear again. So there could be Higgs particles in the room. Do you agree with this picture?
The Higgs particle plays no role in the mass mechanism. The Higgs field gives a mass to various particles - specifically the fact that its average value is not zero. It is the field that we need to understand, not the particle. A particle is only a means to an end.
The Higgs particle is a perturbation of the Higgs field, and studying a particle can give us an idea of the field.
Virtual Higgs particles are indeed present in the room, but virtual particles are not particles at all, despite the fact that they are so called. The Higgs particles are decently behaved waves on the Higgs field, and the virtual "Higgs" particles are a more general type of field perturbation. The Higgs particles have a certain mass, while the virtual particles do not. So Frank Colus is not that he lied to you, but he did not express it quite correctly. He told you the standard "lie for the good" that theoretical physicists usually tell the public, but it is so different from reality that it confuses people terribly - so I ask you not to pay attention to it.
If mass is created as the particles interact with the Higgs field, moving through it, then what moves - the field or the particle? If a particle is static with respect to the field, does it lose mass?
Regardless of how you move in space, you do not move relative to the Higgs field. It sounds strange, but remember another oddity: regardless of how you move, the light moves relative to you at a speed of 300,000 km / s. Our intuition works incorrectly with space and time - as Einstein guessed it - and there may also be fields that are at rest with respect to all observers!
Therefore, the mass of the particle remains constant regardless of what it does - it is resting relative to you or moving. And this is important because the particle always rests on itself. Therefore, from her point of view, her weight should be maintained.
The analogies describing the connection of the particle mass with the field as movement through a molasses or a room filled with people are not without problems, since it follows from them that the particle must move in order to be influenced by the Higgs field, although in reality this is not so.
Since gravity attracts things in proportion to their mass, and since the Higgs field is responsible for the mass of all things, there must obviously be some deep connection between the Higgs and gravity, isn't it?
A very reasonable guess, but completely wrong. The problem is that this statement combines the notion of gravity of the XVII century, which has long been revised, with an oversimplified concept of the end of the XX century about the origin of the masses of particles. Let me go into the role of teacher and correct the previous statement:
Since gravity attracts things in proportion to the combination of their energy and momentum, and since the Higgs field is responsible for the presence of mass not only in everything, but only in known elementary particles, with the exception of the Higgs particle itself, there is no connection between Higgs and gravity.
I will explain the corrections.
When you first encounter the concept of gravity in school, you learn Newton's law: the force of attraction between two objects, mass M1 and M2, is proportional to the product M1 M2.
But that was before Einstein. It turns out that Newton's law needs to be revised: the Einstein wording roughly corresponds to the fact that for two slowly moving objects (their relative speed is much less than the speed of light c), with energies E1 and E2, the force of their attraction is proportional to the product E1 E2.
How do these statements fit together? Einstein and his followers found that for any ordinary object the relationship between its energy E, momentum p and mass M (it is called “rest mass”, but experts in particle physics call it simply “mass”) is as follows:
For a slowly moving object, p ≈ Mv (v is its speed), and pc ≈ Mvc is much smaller than Mc 2 . Consequently,
(that is, for slow objects E ≈ M c 2 ).
Since the planets, moons and artificial satellites move relative to each other and the Sun with speeds much lower than 0.1% of c, the gravitational attraction between them is proportional to
And since c is a constant, for such objects the laws of attraction of Einstein and Newton fully coincide. Force is proportional to the product of energies and the product of masses, as they are proportional to each other.
But for objects moving at high speeds, or for objects experiencing strong gravitational attraction (which will quickly increase their speed), the Einstein law of attraction involves a complex combination of momentum and energy in which mass does not manifest itself directly. Therefore, Einstein gravity also attracts such things as light, consisting of massless photons. And therefore gravitational waves - waves in space and time, not possessing, in the manner of light, mass - can be formed by objects moving in orbit around each other. Simply put, Einstein's law of gravity, confirmed experimentally, is significantly different from Newton's law; in particular, it is not mass that plays the primary role, but energy and momentum. And for all objects, regardless of what they are made of or how they move,there is energy - therefore everything in the Universe influences through gravity everything else. We say, "gravity is universal interaction."
What about the fact that the Higgs field is responsible for all the mass in the universe? This statement, often found in the press or in popular articles, is incorrect.
And what would be the correct statement? There is a list of known elementary particles. The mass does not have:
• photons,
• gluons,
• gravitons (their presence is still only assumed).
Mass has:
• W and Z particles,
• quarks: upper, lower, enchanted, strange, charming, true,
• charged leptons: electrons, muons, tau,
• neutrino: three types (at least two of them have mass)
• a recently discovered particle of 125 GeV / s 2 mass , which can be considered a Higgs particle of some type.
Particles W and Z, quarks, charged leptons and neutrinos really must have a mass due to the Higgs field. In another way, they can not get a lot. But for the Higgs particle itself this is not the case.
The Higgs particle mass exists not only due to the Higgs field!
And where does it come from? It is a long story, ending not with an answer, but with a question. Until I dwell on it, I will say only that the mass of the Higgs particle does not have a simple, clear and only source, and its surprisingly small mass is one of the facets of a huge puzzle called the “hierarchy problem”.
In any case, the Higgs field is not a universal source of mass for all elementary particles. The Higgs particle gets some of its mass from some other source. And probably not only she. It is very possible that dark matter consists of particles, and that these particles also receive a part of their mass from another source. Dark matter, according to most physicists and astronomers, makes up most of the matter in the universe. It is believed that it is responsible for most of the mass of the Milky Way galaxy, in which we also live. And the Higgs field is likely to make a small contribution to this mass.
Other objects derive their mass from sources unrelated to the Higgs particle. Most of the mass of the atom is contained in the nucleus, and not in the light electrons outside. The nucleus consists of protons and neutrons - bags with quarks, antiquarks and gluons caught in them. These quarks, antiquarks and gluons rush about in their tiny prisons with huge speeds, and the mass of proton and neutron exists due to these energies, as well as the energy needed to hold the quarks and everything else, and the masses of the quarks and antiquarks contained in the bag. Therefore, the proton and neutron masses do not originate predominantly from the Higgs field. So the mass of the Earth and the Sun would have changed only slightly if the Higgs field were not - if they had not collapsed in his absence.
And black holes, one of the most massive objects of the Universe, located in the center of almost all galaxies, in principle, can consist of massless objects. In principle, a black hole can be completely made from photons. In practice, most of the black holes are made of ordinary matter, but the mass of ordinary matter mainly depends on atomic nuclei, and their mass, as we have already noted, does not fully depend on the Higgs field.
Whatever one may say, the Higgs field is not a universal source of mass for all objects of the Universe - neither for ordinary matter, nor for dark matter, nor for black holes. It gives mass to most of the known fundamental particles, and its presence is critical for the existence of atoms. But interesting gravitational effects in the Universe would be enough without the Higgs field. It simply would not have atoms and people who would study them.
Finally, one can ask whether there is a mathematical connection between gravity and the Higgs field in any equations. The answer is no.At gravitational fields, the spin is 2, they are described as part of space and time. They interact with all particles and fields. At the Higgs field, the spin is 0, it interacts directly with the elementary particles and fields involved in electromagnetic and weak interactions.
So, the thought of the Higgs connection and gravity is natural for a person who is not an expert, but naive. It stems from a misunderstanding of:
• Field Higgs, which does not have a universal action. It imparts mass to most of the known elementary particles, but not to the Higgs particle, not to protons and neutrons, not dark matter (most likely) and black holes;
• Einstein gravity, universal, and working with energy and momentum, but not directly with mass attracting protons and neutrons, dark matter and black holes, although their masses exist not only due to the Higgs field.
It turns out that despite the superficial similarity, the relationship between gravity and Higgs is very weak.
If we are looking for reasons for which elementary particles have a certain mass, why are we not looking for reasons for which they have a certain charge and spin?
We are looking for them. But in quantum field theory (in the equations used in particle physics), the mass is very different from charge and spin. The charge and spin of the particles are fixed and determined. And the mass can smoothly change from zero to non-zero values, and in the second case, the exact mass is determined, by a complex quantum-mechanical method, through the force and nature of the interactions of this particle with all the others. Therefore, the question of where mass is taken from and the magnitude of interactions in nature is very different from the question of where charge and spin come from.
Was the value of the Higgs field always nonzero?
It depends on the history of the universe, which we have not studied well enough. It is possible that in some very short time the Universe was very hot and the size of the Higgs field was close to zero. It is even possible that for a short time all the fields we know were mixed beyond recognition (which can occur in a different vacuum of the landscape of the fields, which is sometimes called the " string theory landscape "). Or maybe it happened for a long time. The history of the universe before the Big Bang can be very short or very long, we do not know.
But the Higgs field was non-zero from the moment the Universe cooled down to several billion degrees — and this happened within a small fraction of a second after the Big Bang.
Why don't the Standard Model equations predict the exact mass of the Higgs particle?
In the equations of the Standard Model, one can find several unknown constants. This includes the strength of electromagnetic, weak, and strong nuclear interactions, and the values that determine the masses of known particles (after the Higgs field becomes nonzero). Several other constants determine the decay of some particles. And, finally, the mass of the Higgs particle is not determined.
Most of these values are determined not through equations, but through experiments. You may ask if the Standard Model predicts anything at all, since so much was needed to figure out in experiments. The answer will be: Oh yes, how else !!! We really need to first measure about 20 values, but then the Standard Model produces thousands of successful predictions for a huge variety of experiments. For example, it predicts the masses of the particles W and Z, and how often they occur in experiments at the Large Electron-Positron Collider , the Large Hadron Collider and Tevatron. It predicts the speed and the result of the decay of particles, how exactly all particles of matter decay, the magnetic response of the electron to 12 decimal places, and the muon to 8, how often and how the upper quarks arise, and how they break up ...
To receive thousands of successful predictions based on 20 measurements means to achieve great success. Of course, we want to know where these 20 values come from, and we hope that LHC or other experiments will give us answers.
It should also be borne in mind that the Standard Model contains the simplest possible version of the description of the Higgs field, and it may not coincide with what actually exists in nature. We need not only to deal with the Higgs mass, but also to check how it behaves in reality.
Do you know what a particle is? Field? If not, let's understand.
A field is something
')
1. what is present everywhere in space and time,
2. able to take a zero or non-zero value,
3. that is capable of generating waves in itself.
4. And if this is a quantum field, then these waves are made up of particles.
For example: the electric field is a part of nature, and it can be found everywhere. At any given point in space at any time it can be measured. If in a certain region of space, on average, it is non-zero, it can have a physical effect — lift your hair or cause sparks. An electric field can generate waves in which the magnitude of the field periodically becomes larger and smaller - for example, such a wave is visible light, X-rays, radio waves, and everything else that we generally call "electromagnetic waves."
So what is a particle?
The intensity of the quantum field waves can not be any. They cannot be arbitrarily "weak" or "quiet." The lowest intensity wave that a field is capable of propagating is called a "quantum" or "particle." Often they behave like you intuitively imagine particles - moving in straight lines and bouncing off different things, that's why we called them particles.
In the case of an electric field, its particles are called "photons." They represent the weakest possible outbreak. Your eye can absorb light one photon at a time (although it is usually the arrival of several photons in a row to send a signal to the brain). The laser produces very intense waves, but if you shield the screen from it so that a small part of the light passes through it, you can find that the light passes through the screen in small bursts — single photons — and they are all equally dull.
I sort of got it. The Higgs wave is a perturbation of the Higgs field, and the Higgs particle is the smallest, weakest wave.
Exactly. Sorry for such a short version of the story. In the following articles there will be explanations about particles using mathematical calculations and physical bases.
Why are particle physics experts so interested in the Higgs particle?
In fact, they are not interested in her. They are interested in the Higgs field, it is extremely important for them.
Why is the Higgs field so important?
The Higgs field, unlike the most elementary fields of nature, has a non-zero average value throughout the Universe. Because of this, many particles have a mass, including an electron, quarks, and particles of weak interaction W and Z. If the average value of the Higgs field was zero, these particles would be massless or very light. That would be a disaster; atoms and atomic nuclei would disintegrate. Nothing like humans or the Earth on which we live could exist without a non-zero Higgs field average. Our lives depend on it.
What do we know about the Higgs field?
Almost nothing. Basically what it is, and that its value is non-zero. We have some information about how it interacts with matter, but not too much. The recent discovery of what may be his outrage - the Higgs particles - can give us more information.
If the Higgs field is so important, why is there so much noise around the Higgs particle?
On the one hand, finding the Higgs particle (or something instead of it — details below) is the simplest (and probably the only) way for physicists to study the Higgs field — and that’s what we need. In this sense, the detection of the Higgs particle is the first big step towards the main goal: understanding the properties of the Higgs field and the reasons for its non-zero average value.
On the other hand, modern media insist on inflating the hype. And since the explanation of the Higgs field and its role and connection with the Higgs particle takes up too much space for a typical news report, journalists, as well as people communicating with them, reduce all this information. As a result, the Higgs particle receives all the attention, and the unfortunate Higgs field works in obscurity, protecting the Universe from disaster and not receiving the deserved respect ...
Are physicists confident in the existence of the Higgs field?
Yes, although this is a point that needs special comment. On the basis of many experiments and their successful interpretations with the help of mathematical equations, we are sure that there is a certain field with a non-zero average value that gives mass to the electron, W, Z particles, and many others, and allows our world to exist with us. The evidence is indisputable. By default, we call this field the "Higgs field."
But we do not know much. For example:
• There may be one Higgs field, or there may be several — each with its own particle.
• The Higgs field can be a composite of several other fields. There are such examples in nature: if a proton is a composite object consisting of quarks, antiquarks and gluons, then the proton field is a composite field consisting of quark, antiquark and gluon fields. We do not know whether the Higgs field is elementary, like an electric field, or whether it is a composite field like that of a proton.
The only way to find out the number of Higgs fields and their elementary nature, as well as how they interact with particles known to us, and possibly with unknowns, is to conduct an experiment: the Large Hadron Collider, or LHC.
What is "elementary"?
Unfortunately, the answer is looped back: it means "not composite." It cannot be broken down into more elementary parts. More precisely, it can not be divided into parts with the help of our existing technology. (People used to think that protons are elementary. Before that, they thought that atoms were elementary - hence the “Periodic Table of Elements”).
Are physicists confident in the existence of the Higgs particle?
Previously, we were not sure of this, and its existence was essentially proved only by an experiment from July 2012.
And in the past we were sure that:
1. There is at least one type of Higgs particle, and we will find it (them) at the LHC, or
2. The Higgs particles decay too quickly for us to detect them, but only because they are greatly influenced by new particles and the forces that we can find in the LHC!
Now we have learned something: the second option was wrong. And although there might not have been a Higgs particle in nature, it seems to exist. And now, in order to learn more about the Higgs field, we need to understand whether there are other types of Higgs particles, and what are the properties of the found particle.
The press and many physicists claim that the LHC was built to search for the Higgs particle. And since they found her, did the BAC finish their work?
All this is not true. It is true that the LHC was built in order to understand what the Higgs field (or fields) is, how it works and elementary or composite. Finding a Higgs particle is one way to find out. Do not confuse goals and means. The ultimate goal is an understanding of the field. Search and study of a particle are the means, and at the LHC there is still a lot left to do, including the study of the found particle and possible discoveries of new ones.
Did you really find the Higgs particle?
Similarly, we can say the following:
1. Using the data obtained in 2011 and the beginning of 2012, the scientists discovered a new particle at the LHC.
2. This particle has not yet been very well studied, but it behaves as expected from the Higgs boson.
3. It also behaves according to how the simplest type of Higgs particles should behave - the so-called. Higgs particle from the Standard Model.
While scientists conduct additional research of this particle. These studies will also help us in expanding our understanding of the Higgs field. In addition, we will continue to search for other Higgs particles that are harder to find. The fact that we have yet found one does not mean that there cannot be two, five or twelve!
Do you really, in all honesty, solemnly swear that you are convinced that there is a Higgs field in nature?
Yes Yes Yes. I rarely say anything in absolute terms, but here I say yes. If you try to remove the Higgs field from mathematics, but leave W, Z and other heavy particles (such as the top quark) that we already discovered and are present in nature, it turns out that the mathematics of the Standard Model does not make sense. It turns out a theory that predicts that certain processes (including those that can be studied at the LHC) can occur with a probability greater than 1. And this is impossible and illogical. The probability of something, obviously, cannot be more than one or less than zero.
You may be surprised, but it is very difficult to make logically consistent theories. Most theories begin to predict events with probability less than zero or greater than one. Only a very small number makes sense.
To restore the Standard Model to its working state, you must add the Higgs field, or something like it, to the fields already open in the experiments. But this can be done in many ways, and the only way to determine which of them is correct is to conduct an experiment, namely, LHC!
Why is the Higgs particle often called the "Higgs boson"?
All particles in nature, elementary or not, can be divided into two classes, fermions and bosons (although in some solid materials there are very strange exceptions). It so happened that the Higgs particle is a boson. But in terms of what it does and why we need to look for it and study it, it is not so important.
Why is the Higgs particle called the “God particle”?
Because in the media they believe that it sounds cool and that it makes readers pay attention to their articles. The origin of this nickname is as unreligious and unscientific as you can imagine: it was invented as an advertisement. Professor, Nobel Prize winner, Leon Lederman, a very important experimental physicist who deserves great respect for his contribution to science, deserves also every censure for his book on the Higgs particle [The God Particle: Is the Question?] Got such a catchy headline. It is somewhere between indecency and blasphemy, depending on your upbringing. When I, while studying at the institute, first heard how he used this nickname during his lecture, my jaw just dropped. I already knew enough about physics to understand how absurd it was.
I have never seen or heard a physicist, thus mentioning a Higgs particle in any context — in scientific work, in a report at a conference, or even in an informal scientific discussion. Nothing in mathematical equations, in the interpretation of physics, in any of the philosophies I know, in religious texts and traditions I know of, does not unite a particle or Higgs field with concepts of religion or deity. This nickname came up from scratch.
Personally, I think that neither science nor religion should be change coins due to the fact that book publishers need to sell books, and the media - articles. The sooner we abandon this idea, the better.
I heard that the Higgs particle disintegrates very quickly, so how can it create or maintain the Higgs field? From what I read, it seems to be that there is a sea of Higgs particles, which in some way create the Higgs field. But it will not work if the Higgs particle ceases to exist very quickly.
The Higgs field does not need to be created in any process; it simply is, just as an electric field exists, everywhere and always.
The Higgs field has a non-zero mean value (and an electric value has a zero value). This nonzero value is also simply "is." It does not need to be created in any process. It is simply the preferred state of the universe for the Higgs field. We do not know why this is happening, but for this, no one should do anything.
No need to imagine the non-zero value of the Higgs field as a sea of Higgs particles; it is not right. The Higgs particle is a perturbation of a field of minimal intensity. The perturbation changes in space and time, like any wave. But the non-zero value of the Higgs field does not change in space and time, it is a constant. A good analogy: air density is a field. He has a constant average. Waves in the air are sound waves. And it makes no sense to assume that the average air density is somehow created by a sea of sound waves, fleeting air vibrations.
Higgs particles do not form spontaneously. For this you need to expend energy. You need to use something like a proton collision on the LHC to hit the Higgs field and make it vibrate, just like clapping your hands to make a sound, hit the surface of the lake to create a wave, or pull the violin string to vibrate . Just as the wave goes out after a while, and the string of the violin stops vibrating, so the Higgs particle disintegrates. The air, the lake, the strings of the violin and the Higgs field remain after the vibration dissipates.
Then it turns out that Higgs particles do not exist in nature? Apparently, therefore, you wrote that in the room where I am, there are no Higgs particles, but my electrons have mass. And what is the role of the Higgs particle in the mass mechanism? I thought that they somehow transferred the interaction, such as W for weak interaction, but it seems that the Higgs particle is not suitable for this. And in one lecture I asked Frank Close, if there were any Higgs particles in the room, and he mentioned that they could appear, “taking over” energy for a while, and then disappear again. So there could be Higgs particles in the room. Do you agree with this picture?
The Higgs particle plays no role in the mass mechanism. The Higgs field gives a mass to various particles - specifically the fact that its average value is not zero. It is the field that we need to understand, not the particle. A particle is only a means to an end.
The Higgs particle is a perturbation of the Higgs field, and studying a particle can give us an idea of the field.
Virtual Higgs particles are indeed present in the room, but virtual particles are not particles at all, despite the fact that they are so called. The Higgs particles are decently behaved waves on the Higgs field, and the virtual "Higgs" particles are a more general type of field perturbation. The Higgs particles have a certain mass, while the virtual particles do not. So Frank Colus is not that he lied to you, but he did not express it quite correctly. He told you the standard "lie for the good" that theoretical physicists usually tell the public, but it is so different from reality that it confuses people terribly - so I ask you not to pay attention to it.
If mass is created as the particles interact with the Higgs field, moving through it, then what moves - the field or the particle? If a particle is static with respect to the field, does it lose mass?
Regardless of how you move in space, you do not move relative to the Higgs field. It sounds strange, but remember another oddity: regardless of how you move, the light moves relative to you at a speed of 300,000 km / s. Our intuition works incorrectly with space and time - as Einstein guessed it - and there may also be fields that are at rest with respect to all observers!
Therefore, the mass of the particle remains constant regardless of what it does - it is resting relative to you or moving. And this is important because the particle always rests on itself. Therefore, from her point of view, her weight should be maintained.
The analogies describing the connection of the particle mass with the field as movement through a molasses or a room filled with people are not without problems, since it follows from them that the particle must move in order to be influenced by the Higgs field, although in reality this is not so.
Since gravity attracts things in proportion to their mass, and since the Higgs field is responsible for the mass of all things, there must obviously be some deep connection between the Higgs and gravity, isn't it?
A very reasonable guess, but completely wrong. The problem is that this statement combines the notion of gravity of the XVII century, which has long been revised, with an oversimplified concept of the end of the XX century about the origin of the masses of particles. Let me go into the role of teacher and correct the previous statement:
Since gravity attracts things in proportion to the combination of their energy and momentum, and since the Higgs field is responsible for the presence of mass not only in everything, but only in known elementary particles, with the exception of the Higgs particle itself, there is no connection between Higgs and gravity.
I will explain the corrections.
When you first encounter the concept of gravity in school, you learn Newton's law: the force of attraction between two objects, mass M1 and M2, is proportional to the product M1 M2.
But that was before Einstein. It turns out that Newton's law needs to be revised: the Einstein wording roughly corresponds to the fact that for two slowly moving objects (their relative speed is much less than the speed of light c), with energies E1 and E2, the force of their attraction is proportional to the product E1 E2.
How do these statements fit together? Einstein and his followers found that for any ordinary object the relationship between its energy E, momentum p and mass M (it is called “rest mass”, but experts in particle physics call it simply “mass”) is as follows:
For a slowly moving object, p ≈ Mv (v is its speed), and pc ≈ Mvc is much smaller than Mc 2 . Consequently,
(that is, for slow objects E ≈ M c 2 ).
Since the planets, moons and artificial satellites move relative to each other and the Sun with speeds much lower than 0.1% of c, the gravitational attraction between them is proportional to
And since c is a constant, for such objects the laws of attraction of Einstein and Newton fully coincide. Force is proportional to the product of energies and the product of masses, as they are proportional to each other.
But for objects moving at high speeds, or for objects experiencing strong gravitational attraction (which will quickly increase their speed), the Einstein law of attraction involves a complex combination of momentum and energy in which mass does not manifest itself directly. Therefore, Einstein gravity also attracts such things as light, consisting of massless photons. And therefore gravitational waves - waves in space and time, not possessing, in the manner of light, mass - can be formed by objects moving in orbit around each other. Simply put, Einstein's law of gravity, confirmed experimentally, is significantly different from Newton's law; in particular, it is not mass that plays the primary role, but energy and momentum. And for all objects, regardless of what they are made of or how they move,there is energy - therefore everything in the Universe influences through gravity everything else. We say, "gravity is universal interaction."
What about the fact that the Higgs field is responsible for all the mass in the universe? This statement, often found in the press or in popular articles, is incorrect.
And what would be the correct statement? There is a list of known elementary particles. The mass does not have:
• photons,
• gluons,
• gravitons (their presence is still only assumed).
Mass has:
• W and Z particles,
• quarks: upper, lower, enchanted, strange, charming, true,
• charged leptons: electrons, muons, tau,
• neutrino: three types (at least two of them have mass)
• a recently discovered particle of 125 GeV / s 2 mass , which can be considered a Higgs particle of some type.
Particles W and Z, quarks, charged leptons and neutrinos really must have a mass due to the Higgs field. In another way, they can not get a lot. But for the Higgs particle itself this is not the case.
The Higgs particle mass exists not only due to the Higgs field!
And where does it come from? It is a long story, ending not with an answer, but with a question. Until I dwell on it, I will say only that the mass of the Higgs particle does not have a simple, clear and only source, and its surprisingly small mass is one of the facets of a huge puzzle called the “hierarchy problem”.
In any case, the Higgs field is not a universal source of mass for all elementary particles. The Higgs particle gets some of its mass from some other source. And probably not only she. It is very possible that dark matter consists of particles, and that these particles also receive a part of their mass from another source. Dark matter, according to most physicists and astronomers, makes up most of the matter in the universe. It is believed that it is responsible for most of the mass of the Milky Way galaxy, in which we also live. And the Higgs field is likely to make a small contribution to this mass.
Other objects derive their mass from sources unrelated to the Higgs particle. Most of the mass of the atom is contained in the nucleus, and not in the light electrons outside. The nucleus consists of protons and neutrons - bags with quarks, antiquarks and gluons caught in them. These quarks, antiquarks and gluons rush about in their tiny prisons with huge speeds, and the mass of proton and neutron exists due to these energies, as well as the energy needed to hold the quarks and everything else, and the masses of the quarks and antiquarks contained in the bag. Therefore, the proton and neutron masses do not originate predominantly from the Higgs field. So the mass of the Earth and the Sun would have changed only slightly if the Higgs field were not - if they had not collapsed in his absence.
And black holes, one of the most massive objects of the Universe, located in the center of almost all galaxies, in principle, can consist of massless objects. In principle, a black hole can be completely made from photons. In practice, most of the black holes are made of ordinary matter, but the mass of ordinary matter mainly depends on atomic nuclei, and their mass, as we have already noted, does not fully depend on the Higgs field.
Whatever one may say, the Higgs field is not a universal source of mass for all objects of the Universe - neither for ordinary matter, nor for dark matter, nor for black holes. It gives mass to most of the known fundamental particles, and its presence is critical for the existence of atoms. But interesting gravitational effects in the Universe would be enough without the Higgs field. It simply would not have atoms and people who would study them.
Finally, one can ask whether there is a mathematical connection between gravity and the Higgs field in any equations. The answer is no.At gravitational fields, the spin is 2, they are described as part of space and time. They interact with all particles and fields. At the Higgs field, the spin is 0, it interacts directly with the elementary particles and fields involved in electromagnetic and weak interactions.
So, the thought of the Higgs connection and gravity is natural for a person who is not an expert, but naive. It stems from a misunderstanding of:
• Field Higgs, which does not have a universal action. It imparts mass to most of the known elementary particles, but not to the Higgs particle, not to protons and neutrons, not dark matter (most likely) and black holes;
• Einstein gravity, universal, and working with energy and momentum, but not directly with mass attracting protons and neutrons, dark matter and black holes, although their masses exist not only due to the Higgs field.
It turns out that despite the superficial similarity, the relationship between gravity and Higgs is very weak.
If we are looking for reasons for which elementary particles have a certain mass, why are we not looking for reasons for which they have a certain charge and spin?
We are looking for them. But in quantum field theory (in the equations used in particle physics), the mass is very different from charge and spin. The charge and spin of the particles are fixed and determined. And the mass can smoothly change from zero to non-zero values, and in the second case, the exact mass is determined, by a complex quantum-mechanical method, through the force and nature of the interactions of this particle with all the others. Therefore, the question of where mass is taken from and the magnitude of interactions in nature is very different from the question of where charge and spin come from.
Was the value of the Higgs field always nonzero?
It depends on the history of the universe, which we have not studied well enough. It is possible that in some very short time the Universe was very hot and the size of the Higgs field was close to zero. It is even possible that for a short time all the fields we know were mixed beyond recognition (which can occur in a different vacuum of the landscape of the fields, which is sometimes called the " string theory landscape "). Or maybe it happened for a long time. The history of the universe before the Big Bang can be very short or very long, we do not know.
But the Higgs field was non-zero from the moment the Universe cooled down to several billion degrees — and this happened within a small fraction of a second after the Big Bang.
Why don't the Standard Model equations predict the exact mass of the Higgs particle?
In the equations of the Standard Model, one can find several unknown constants. This includes the strength of electromagnetic, weak, and strong nuclear interactions, and the values that determine the masses of known particles (after the Higgs field becomes nonzero). Several other constants determine the decay of some particles. And, finally, the mass of the Higgs particle is not determined.
Most of these values are determined not through equations, but through experiments. You may ask if the Standard Model predicts anything at all, since so much was needed to figure out in experiments. The answer will be: Oh yes, how else !!! We really need to first measure about 20 values, but then the Standard Model produces thousands of successful predictions for a huge variety of experiments. For example, it predicts the masses of the particles W and Z, and how often they occur in experiments at the Large Electron-Positron Collider , the Large Hadron Collider and Tevatron. It predicts the speed and the result of the decay of particles, how exactly all particles of matter decay, the magnetic response of the electron to 12 decimal places, and the muon to 8, how often and how the upper quarks arise, and how they break up ...
To receive thousands of successful predictions based on 20 measurements means to achieve great success. Of course, we want to know where these 20 values come from, and we hope that LHC or other experiments will give us answers.
It should also be borne in mind that the Standard Model contains the simplest possible version of the description of the Higgs field, and it may not coincide with what actually exists in nature. We need not only to deal with the Higgs mass, but also to check how it behaves in reality.
Source: https://habr.com/ru/post/370513/
All Articles